A comprehensive TeX system that you can install on your hard disk. It includes support for most Unix system architectures, including GNU/Linux, and for Windows. The MacTeX distribution is developed as part of the TeX live effort, and has similar properties, but is distributed separately.

The TeX, PDFeTeX, XeTeX and LuaTeX engines are provided in the distribution, with several different running formats each; a wide range of support programs and macro packages is also included.

Beware: the download is large (>2 Gbytes); it comes in the form of an ISO image for a DVD.

See also texlive-source.

The author is The TeX-live team.